Electronic commerce, commonly known as e-commerce, has become a popular way of shopping for many in recent years. Most e-commerce merchants require a user, or e-commerce customer, to create an e-commerce customer account for conducting transactions, e.g., purchase and/or sale of goods, on the e-commerce website maintained by the e-commerce merchant. An e-commerce customer account typically includes credentials such as user name and password for login onto a respective e-commerce website. For security or other reasons, the same e-commerce customer may have different user names and/or passwords for various e-commerce websites. From time to time, an e-commerce customer may forget his/her login credentials for a given e-commerce website and, under the circumstances, the e-commerce customer may establish a new user name and/or password for the e-commerce website the login credentials for which he/she forgot. In other words, the same e-commerce customer ends up with more than one e-commerce customer accounts, or profiles, for the same e-commerce website. From the perspective of the e-commerce merchant, however, this situation is not desirable at least for the purposes of targeting and providing recommendations to e-commerce customers. Moreover, the existence of duplicate profiles for the same e-commerce customer introduces artificial sparseness in the customer-to-item relationship from the e-commerce merchant's perspective.